1. Technical Field of the Invention
The present invention relates to a method and apparatus for manufacturing an electro-optical device formed with an insulating film or alignment layer on a substrate, and a method and apparatus for manufacturing a liquid crystal panel, more particularly, a method and apparatus for manufacturing an electro-optical device capable of uniformly depositing the insulating film or alignment layer, and a method and apparatus for manufacturing a liquid crystal panel capable of efficiently cleaning the alignment layer.
2. Description of the Related Art
Currently, in electronic devices such as mobile telephones and mobile electronic terminals, liquid crystal devices are widely used for displaying information such as characters, numerals and icons. Such liquid crystal devices are generally provided with a liquid crystal panel sealed with liquid crystals between a pair of liquid crystal substrates formed with electrodes on the inner surfaces, and have a configuration where a voltage is applied to the liquid crystals sealed inside the liquid crystal panel with the voltage controlled and thereby the alignment of the liquid crystals is controlled to modulate light incident into the liquid crystals.
In such liquid crystal devices, in addition to the above-mentioned electrodes for applying a voltage to liquid crystals, an insulating film for ensuring insulation between two layers and an alignment layer for forming the alignment of liquid crystals (aligning liquid crystals in a predetermined direction) are deposited on the inner outside face (surface) of the liquid crystal substrates. In general, inorganic materials such as metal oxide and the like are used as materials for the insulating film, and organic materials such as polyimide and the like are used as the alignment layer.
Additionally, to the surface of the alignment layer described above, a so-called rubbing process(for example, process of rubbing with cloth etc.) is applied. It is considered that the rubbing process forms fine grooves on the surface of the alignment layer, liquid crystals are aligned along the direction of the grooves and thereby a predetermined alignment is achieved.
However, when the insulating film or alignment layer is directly deposited on the surface of a glass substrate, there has been a problem that the inorganic materials such as metal oxide and the like for the insulating film material or organic material such as polyimide and the like for the alignment layer material has a low wettability to the glass substrate and it is difficult to uniformly deposit the insulating film or alignment layer on the surface of the glass substrate.
Additionally, during the rubbing process, dust or dirt such as a fiber of the cloth or the like can be attached on the surface of the alignment layer. Such foreign matters (dusts or dirt) on the surface of the alignment layer are removed by ultrasonic cleaning with pure water after the rubbing process. However, the alignment layer has a hydrophobic property and thus tends to repel water. There is the case where the foreign matters are gathered in air bubbles on the alignment layer, and sometimes remain inside the liquid crystal panel unremoved. There has been a problem that the foreign matters which thus remain cause defects regarding the alignment property of liquid crystals.
The purpose of the invention is to provide a method and an apparatus for manufacturing an electro-optical device capable of uniformly depositing an insulating film or alignment layer on the surface of the substrate, and a method and an apparatus for manufacturing a liquid crystal panel capable of efficiently cleaning the alignment layer.